There is a summary document on database Server patchsets from 8.1.7.4 and after. It is a good resource for identifying patch numbers of RDBMS PSU, SPU(CPU), Bundle patches and Patchsets.
The Metalink note number is 438049.1. Seems Oracle updates this document all the time.
Monday, June 22, 2009
Tuesday, June 16, 2009
Select MAX from a column
I tried using below function to get a sequence value for a coulmn, but kept getting NULL when when the table is empty.
begin
select max(nvl(id, 0)) + 1 INTO t_id FROM table_name;
exception when NO_DATA_FOUND then
t_id := 1;
end;
The real trick is that "select max(id) FROM table_name" always returns NULL, and does not raise NO_DATA_FOUND error.
The fix is to use below statement:
select nvl(max(id), 0) + 1 INTO t_id FROM table_name;
Note "select count(id) from table_name" always returns 0 when the table is empty.
begin
select max(nvl(id, 0)) + 1 INTO t_id FROM table_name;
exception when NO_DATA_FOUND then
t_id := 1;
end;
The real trick is that "select max(id) FROM table_name" always returns NULL, and does not raise NO_DATA_FOUND error.
The fix is to use below statement:
select nvl(max(id), 0) + 1 INTO t_id FROM table_name;
Note "select count(id) from table_name" always returns 0 when the table is empty.
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